In case of UDP links, the local or remote endpoint used to communicate
with a given peer may change without a connection restart.
Add support for learning the new address in case of change.
Signed-off-by: Antonio Quartulli <anto...@openvpn.net>
---
drivers/net/ovpn/io.c | 8 ++
drivers/net/ovpn/peer.c | 213 +++++++++++++++++++++++++++++++++++++++++++++---
drivers/net/ovpn/peer.h | 2 +
3 files changed, 210 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ovpn/io.c b/drivers/net/ovpn/io.c
index
fcba094ed412068af88cf74baa82ec2742e0b634..49bb58868053e2d1542a8a5849c4bbc256083efc
100644
--- a/drivers/net/ovpn/io.c
+++ b/drivers/net/ovpn/io.c
@@ -96,6 +96,7 @@ void ovpn_decrypt_post(void *data, int ret)
struct ovpn_crypto_key_slot *ks;
unsigned int payload_offset = 0;
struct sk_buff *skb = data;
+ struct ovpn_socket *sock;
struct ovpn_peer *peer;
__be16 proto;
__be32 *pid;
@@ -137,6 +138,13 @@ void ovpn_decrypt_post(void *data, int ret)
/* keep track of last received authenticated packet for keepalive */
WRITE_ONCE(peer->last_recv, ktime_get_real_seconds());
+ rcu_read_lock();
+ sock = rcu_dereference(peer->sock);
+ if (sock && sock->sock->sk->sk_protocol == IPPROTO_UDP)
+ /* check if this peer changed local or remote endpoint */
+ ovpn_peer_endpoints_update(peer, skb);
+ rcu_read_unlock();
+
/* point to encapsulated IP packet */
__skb_pull(skb, payload_offset);
diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c
index
45e87ac155b554044388490a403f64c777d283a6..0d8b12fd5de4cd6fe15455b435c7d6807203a825
100644
--- a/drivers/net/ovpn/peer.c
+++ b/drivers/net/ovpn/peer.c
@@ -127,6 +127,206 @@ struct ovpn_peer *ovpn_peer_new(struct ovpn_priv *ovpn,
u32 id)
return peer;
}
+/**
+ * ovpn_peer_reset_sockaddr - recreate binding for peer
+ * @peer: peer to recreate the binding for
+ * @ss: sockaddr to use as remote endpoint for the binding
+ * @local_ip: local IP for the binding
+ *
+ * Return: 0 on success or a negative error code otherwise
+ */
+static int ovpn_peer_reset_sockaddr(struct ovpn_peer *peer,
+ const struct sockaddr_storage *ss,
+ const void *local_ip)
+{
+ struct ovpn_bind *bind;
+ size_t ip_len;
+
+ lockdep_assert_held(&peer->lock);
+
+ /* create new ovpn_bind object */
+ bind = ovpn_bind_from_sockaddr(ss);
+ if (IS_ERR(bind))
+ return PTR_ERR(bind);
+
+ if (ss->ss_family == AF_INET) {
+ ip_len = sizeof(struct in_addr);
+ } else if (ss->ss_family == AF_INET6) {
+ ip_len = sizeof(struct in6_addr);
+ } else {
+ net_dbg_ratelimited("%s: invalid family %u for remote endpoint
for peer %u\n",
+ netdev_name(peer->ovpn->dev),
+ ss->ss_family, peer->id);
+ kfree(bind);
+ return -EINVAL;
+ }
+
+ memcpy(&bind->local, local_ip, ip_len);
+
+ /* set binding */
+ ovpn_bind_reset(peer, bind);
+
+ return 0;
+}
+
+/* variable name __tbl2 needs to be different from __tbl1
+ * in the macro below to avoid confusing clang
+ */
+#define ovpn_get_hash_slot(_tbl, _key, _key_len) ({ \
+ typeof(_tbl) *__tbl2 = &(_tbl); \
+ jhash(_key, _key_len, 0) % HASH_SIZE(*__tbl2); \
+})
+
+#define ovpn_get_hash_head(_tbl, _key, _key_len) ({ \
+ typeof(_tbl) *__tbl1 = &(_tbl); \
+ &(*__tbl1)[ovpn_get_hash_slot(*__tbl1, _key, _key_len)];\
+})
+
+/**
+ * ovpn_peer_endpoints_update - update remote or local endpoint for peer
+ * @peer: peer to update the remote endpoint for
+ * @skb: incoming packet to retrieve the source/destination address from
+ */
+void ovpn_peer_endpoints_update(struct ovpn_peer *peer, struct sk_buff *skb)
+{
+ struct hlist_nulls_head *nhead;
+ struct sockaddr_storage ss;
+ struct sockaddr_in6 *sa6;
+ bool reset_cache = false;
+ struct sockaddr_in *sa;
+ struct ovpn_bind *bind;
+ const void *local_ip;
+ size_t salen = 0;
+
+ spin_lock_bh(&peer->lock);
+ bind = rcu_dereference_protected(peer->bind,
+ lockdep_is_held(&peer->lock));
+ if (unlikely(!bind))
+ goto unlock;
+
+ switch (skb->protocol) {
+ case htons(ETH_P_IP):
+ /* float check */
+ if (unlikely(!ovpn_bind_skb_src_match(bind, skb))) {
+ /* unconditionally save local endpoint in case
+ * of float, as it may have changed as well
+ */
+ local_ip = &ip_hdr(skb)->daddr;
+ sa = (struct sockaddr_in *)&ss;
+ sa->sin_family = AF_INET;
+ sa->sin_addr.s_addr = ip_hdr(skb)->saddr;
+ sa->sin_port = udp_hdr(skb)->source;
+ salen = sizeof(*sa);
+ reset_cache = true;
+ break;
+ }
+
+ /* if no float happened, let's double check if the local
endpoint
+ * has changed
+ */
+ if (unlikely(bind->local.ipv4.s_addr != ip_hdr(skb)->daddr)) {
+ net_dbg_ratelimited("%s: learning local IPv4 for peer
%d (%pI4 -> %pI4)\n",
+ netdev_name(peer->ovpn->dev),
+ peer->id, &bind->local.ipv4.s_addr,
+ &ip_hdr(skb)->daddr);
+ bind->local.ipv4.s_addr = ip_hdr(skb)->daddr;
+ reset_cache = true;
+ }
+ break;
+ case htons(ETH_P_IPV6):
+ /* float check */
+ if (unlikely(!ovpn_bind_skb_src_match(bind, skb))) {
+ /* unconditionally save local endpoint in case
+ * of float, as it may have changed as well
+ */
+ local_ip = &ipv6_hdr(skb)->daddr;
+ sa6 = (struct sockaddr_in6 *)&ss;
+ sa6->sin6_family = AF_INET6;
+ sa6->sin6_addr = ipv6_hdr(skb)->saddr;
+ sa6->sin6_port = udp_hdr(skb)->source;
+ sa6->sin6_scope_id =
ipv6_iface_scope_id(&ipv6_hdr(skb)->saddr,
+ skb->skb_iif);
+ salen = sizeof(*sa6);
+ reset_cache = true;
+ break;
+ }
+
+ /* if no float happened, let's double check if the local
endpoint
+ * has changed
+ */
+ if (unlikely(!ipv6_addr_equal(&bind->local.ipv6,
+ &ipv6_hdr(skb)->daddr))) {
+ net_dbg_ratelimited("%s: learning local IPv6 for peer
%d (%pI6c -> %pI6c\n",
+ netdev_name(peer->ovpn->dev),
+ peer->id, &bind->local.ipv6,
+ &ipv6_hdr(skb)->daddr);
+ bind->local.ipv6 = ipv6_hdr(skb)->daddr;
+ reset_cache = true;
+ }
+ break;
+ default:
+ goto unlock;
+ }
+
+ if (unlikely(reset_cache))
+ dst_cache_reset(&peer->dst_cache);
+
+ /* if the peer did not float, we can bail out now */
+ if (likely(!salen))
+ goto unlock;
+
+ if (unlikely(ovpn_peer_reset_sockaddr(peer,
+ (struct sockaddr_storage *)&ss,
+ local_ip) < 0))
+ goto unlock;
+
+ net_dbg_ratelimited("%s: peer %d floated to %pIScp",
+ netdev_name(peer->ovpn->dev), peer->id, &ss);
+
+ spin_unlock_bh(&peer->lock);
+
+ /* rehashing is required only in MP mode as P2P has one peer
+ * only and thus there is no hashtable
+ */
+ if (peer->ovpn->mode == OVPN_MODE_MP) {
+ spin_lock_bh(&peer->ovpn->lock);
+ spin_lock_bh(&peer->lock);
+ bind = rcu_dereference_protected(peer->bind,
+ lockdep_is_held(&peer->lock));
+ if (unlikely(!bind)) {
+ spin_unlock_bh(&peer->lock);
+ spin_unlock_bh(&peer->ovpn->lock);
+ return;
+ }
+
+ /* This function may be invoked concurrently, therefore another
+ * float may have happened in parallel: perform rehashing
+ * using the peer->bind->remote directly as key
+ */
+
+ switch (bind->remote.in4.sin_family) {
+ case AF_INET:
+ salen = sizeof(*sa);
+ break;
+ case AF_INET6:
+ salen = sizeof(*sa6);
+ break;
+ }
+
+ /* remove old hashing */
+ hlist_nulls_del_init_rcu(&peer->hash_entry_transp_addr);
+ /* re-add with new transport address */
+ nhead = ovpn_get_hash_head(peer->ovpn->peers->by_transp_addr,
+ &bind->remote, salen);
+ hlist_nulls_add_head_rcu(&peer->hash_entry_transp_addr, nhead);
+ spin_unlock_bh(&peer->lock);
+ spin_unlock_bh(&peer->ovpn->lock);
+ }
+ return;
+unlock:
+ spin_unlock_bh(&peer->lock);
+}
+
/**
* ovpn_peer_release_rcu - RCU callback performing last peer release steps
* @head: RCU member of the ovpn_peer
@@ -230,19 +430,6 @@ static struct in6_addr ovpn_nexthop_from_skb6(struct
sk_buff *skb)
return rt->rt6i_gateway;
}
-/* variable name __tbl2 needs to be different from __tbl1
- * in the macro below to avoid confusing clang
- */
-#define ovpn_get_hash_slot(_tbl, _key, _key_len) ({ \
- typeof(_tbl) *__tbl2 = &(_tbl); \
- jhash(_key, _key_len, 0) % HASH_SIZE(*__tbl2); \
-})
-
-#define ovpn_get_hash_head(_tbl, _key, _key_len) ({ \
- typeof(_tbl) *__tbl1 = &(_tbl); \
- &(*__tbl1)[ovpn_get_hash_slot(*__tbl1, _key, _key_len)];\
-})
-
/**
* ovpn_peer_get_by_vpn_addr4 - retrieve peer by its VPN IPv4 address
* @ovpn: the openvpn instance to search
diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h
index
e747c4b210642db990222986a80bb37c9a0413fe..f1288734ff100ee76b0c41ebb6dc71725ea33261
100644
--- a/drivers/net/ovpn/peer.h
+++ b/drivers/net/ovpn/peer.h
@@ -153,4 +153,6 @@ bool ovpn_peer_check_by_src(struct ovpn_priv *ovpn, struct
sk_buff *skb,
void ovpn_peer_keepalive_set(struct ovpn_peer *peer, u32 interval, u32
timeout);
void ovpn_peer_keepalive_work(struct work_struct *work);
+void ovpn_peer_endpoints_update(struct ovpn_peer *peer, struct sk_buff *skb);
+
#endif /* _NET_OVPN_OVPNPEER_H_ */
--
2.48.1
